Fig. 3. Free energy diagrams for (A and B) forming 1/4 ML vN yielding 1/4 ML NH*x and (C and D) hydrogenating NH*x–1 to NH*x and y = 0 (circles), 1/4 (diamonds), 1/2 (squares), and 3/4 (triangles) ML H* adatoms on (A and C) Mn2N(0001) and (B and D) Sr2N(0001) at 25 °C and 1 bar. Lines are a guide only. The shaded regions mark energetically favourable surface reactions.
